Sound recording and reproducing system



J. RLQDE LA co|x 1,928,850

SOUND RECORDING AND REPRODUCING SYSTEM Oct. 3, 1933.

Filed May 26, 1930 Sheets-Sheet 1 AUDI D-I NT ERRUPTER N21 ERPUPIER N22i MUNITO R a if 25 BIO-SELECTOR 24 Oct. 3, 1933. J. R. DE LA CROIX 1,923,850 SOUND RECORDING AND REPRODUCING SYSTEM Filed May 26, 1950 5 Sheets-Sheet 2 AUDIU-INTERRUPTER N15 j.

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' STAG E-HICROPHUNE RECORDER CIRCUIT STAGE DIRECTORS MICROPHONE L ZZ .........J

INVENTOR. 3.504%00 A- ORNEY;

Oct. 3, 1933. J )5 LA CRQIX 1,928,850

SOUND RECORDING AND REPRODUCING SYSTEM Filed May 26,1930 5 Sheets-Sheet 5 i INVENTOR. J, W Dz (aw/ix, I BY ATTORNEY 1 1933- J. R. DE LA cRolx 1,928,850

SOUND RECORDING AND REPRODUCING SYSTEM Filed May 26, 1950 5 Sheets-Sheet 4' INVENTOR. $444M?! 434/14 (910w,

RNEY

1933. J. R. DE LA CROIX 1,928,350

SOUND RECORDING AND REPRODUCING SYSTEM Filed May 26, 1930 5 Sheets-Sheet s IN V EN TOR.

A TTORNEY Patented Oct. 3, 1933 SOUND RECORDING AND BEPRODUCING SYSTEM Joseph Renault de la Croix, New York, N. Y.

Application May 26, 1930. Serial No. 455,925

5 Claims. (Cl. 179-1001) My invention relates broadly-to sound recording and reproduction. systems and more particularly to a system of sound recording wherein undesired voicesand noises which may occur ad- 5 jace'nt the pickup microphone may be eliminated in the final recording process.

One of the objects of my invention is to provide a system of sound recording in which the recorded sounds maybe independent of inherent l noises; oral instructions or other sounds incident to the production of a sound program.

Another'object of my invention is to provide a simplified circuit arrangement for a sound recording system by which undesired sounds inherent to the recording of sound programs may be eliminated in the final reproduction process.

Still another object of my invention is to provide a construction of electrical apparatus which may be employed in the recording circuits of a sound recording program system by which the effects of oral instructions which may be issued adjacent the pickup microphone or other sounds adjacent the pickup microphone may be eliminated in the sound reproduction process.

A further object of my invention is to provide a sound program system in which selective means may be introduced in the circuits of the sound recording or projecting apparatus for eliminating undesired sounds from the sound program while reproducing the desired sounds in the sound program.

A still further object of my invention is to provide a construction of light sensitive cell and -mechanical shutter equipment which may be operated in ,the circuits of a sound program recording system for activating the recording circuits automatically to render the recording system effective for a desired sound program independent of inherent noises, oral instructions or other sounds occurring adjacent the pick-up microphone but which sounds are undesired in the final reproduction process.

Other and further objects of my invention will be understood from the specification hereinafter following by reference to the accompanying drawings, wherein:

Figures 1 and la, diagrammatically illustrate a sound recording system embodying the principles of my invention; Fig. 2 is a horizontal sectional view taken substantially on line 2--2 of 'Fig. 3; Fig. 3 is a horizontal vertical sectional view substantially on line 3-3 of Fig. 2, parts of the vertical moving shutters being omitted to avoid confusion; Fig. 4 is a rear end elevation of the outer vertical moving shutter; Fig. 5 is a side. elevation thereof; Fig. 6 is a top plan view thereof Fig. 7 is a horizontal sectional view taken on line 77 of Fig. 5; Fig. 8 is a rear elevation of the inner vertical moving shutter; Fig. 9 is a longitudinal section taken on line 9-9 of Fig. 8; Fig. 10 is a side elevation of the horizontal'moving shutter; Fig. 11 is a transverse vertical sectional view on line 11-11 of Fig. 10; Fig. 12 is a horizontal sectional view taken on line 12-12 of Fig. 10; Fig. 13, is an elevation of the perforated plate working in conjunction with the shutters; Fig. 14 is a horizontal sectional view taken on line 1414 of Fig. 13; and Fig. 15 is a fragmentary sectional view of a portion of the audioselector showing the addition -of a third vertical moving shutter and the elimination of the perforated plate of Fig. 13,.

In the recording of sound programs difliculty has heretofore been experienced in excluding all unnecessary noises, interfering conversation and 76 oral directions, in the vicinity of the pick-up microphone as such noises serve to interfere with the proper recording of the sound and will be normally recorded simultaneously with the program being recorded and will serve to inherently 80 interfere with the reproduction of the sound program. Heretofore in theart of recording sound it has been necessary to have the artist perform in a substantially sound proof booth and it has been necessary to avoid conversation, oral instructions or other noises from reaching the pick-up microphone which is adjacent the recording artist. Instruction or direction could only be given by signals or instructions displayed within the view of the artist and'outside of the line of vision of the camera. Such attempts are inherently ineffective in imparting to the performer the direction intended. Furthermore in the recording of sound an operator must be continuously on watch at the recording apparatus for maintaining the amplifiers and other recording equipment in proper condition, and this operator who serves as a monitor is so isolated from the artist that he is unable to impart any instruction to the artist which might serve to render the reproduction process more nearly perfect. Defects in the recording which may be observed by the monitor must gounchecked and often results in failure of the recording process and requires the retaking of the sound program. Artists performing for a sound program normally perform in a substantially silent surrounding, which is not the atmosphere or environment required to inspire the mental faculties of an artist to produce desired individual characteristics. To introduce music simultaneously with the taking of the sound progra n has heretofore made it necessary that the music be a part of the reproduced sound program which may be wholly inappropriate for the picture which may accompany the sound program.

My invention provides means for imparting instruction to the artist performing for the recording of a sound program with just as much freedom as instruction may he imparted. to the motion picture artist. That is the director is free to instruct the artist with respect to movements or desired sound performance and yet in the reproduction process my system affords means for wholly eliminating the sound of the director's voice. Furthermore, the monitor operator is free to warn the artist with respect to changes in condition in the recording apparatus enabling changes in amplitude, pronunciation of words or movement of the artist with respect to the microphone to be instantly corrected and yet the voice of the monitor according to my process may be eliminated in the reproduction of the sound program. My system also provides means for assisting the artist with an accompaniment of music necessary to create the proper mood in the artist and yet in the reproduction process the musical accompaniment may be eliminated. The circuit arrangements and apparatus which I employ in carrying out the principles of my invention will be understood in more detail as the specification progresses by detailed reference to the drawings.

In Fig. 1, I have indicated the studio in which the sound program originates by reference character 40. The artist performs on the stage 41 and the sound is picked up by pick-up microphone 42. The artist may be photographed while performing for the sound program and the director may, from time to time, instruct the artist from some point in the studio out of the vision of the camera,

the director speaking through the microphone 43.

The microphone 43 is so constructed that the sound of the director's voicedoes not emanate into the studio proper but serves to control the electrical circuit indicated at 44 leading from the studio. For this purpose the microphone 43 is of a form fitting construction which is held closely to the mouth of the director enabling the director to speak therein without setting up direct sound waves in the studio. As will be hereinafter described in more detail the directors voice reaches the artist through a loud speaker indicated at 1 in the studio. Circuit connections extend through audio interrupter No. 1, the details of which are shown more clearly in Figs. 2 and 3. Music is received in the studio from a remotely located music room which I have shown at 45, the music emanating into the studio through a loud speaker designated at 2 through circuits which extend through audio interrupter No. 2. The monitor microphone 46 controls circuits through audio interrupter No. 3 and controls loud speaker 3 in the studio, imparting such instructions to the artist as may be necessary under the conditions of recording. The audio interrupters shown at No. 1, No. 2 and No. 3 are each constructed as illustrated in Figs. 2 and 3.

Referring to Fig. 2, the audio interrupter is shown housed within a casing comprising portions 47, 48 and 49. The housing portion 47 encloses a light sensitive cell designated at 15 located in alignment with the lens 19 and in alignment with lenses 20 and 21 located in housing portion '48 and condenser lenses 22 in housing portion 49. The housing portion 48 includes independent microammeters or sensitive galvanometers designated at 23, 24 and 25. Each of the microammeters have angularly movable members journaled in jeweled bearings and capable of movement under control of current changes through i croammeter 25 is mounted so that the angularly movable element 26 thereof moves in a substantially horizontal plane. element 26 carries a shutter 29 movable'in a horizontal plane. The shutter 29 is provided with an angular slit or aperture 50 as illustrated more clearly in Fig. 11, which slit may be moved across the path of the several lenses 19, 20 and 21 in alignment with the light source 16, the light rays from which are concentrated by reflector 33 in the direction of light sensitive cell 15. The microammeters 23 and 24 have their angularly movable. elements 27 and 28 journaled in jeweled bearings for movement in substantially vertical planes. The movable elements 27 and 28 carry vertical shutters 30 and 31 movable in superimposed relationship with respect to the horizontally movable shutter 29. The arrangement of shutters 29, 30 and 31 will be more clearly understood by reference to Figs. 4-12. In Fig. 8, vertical shutter 30 is shown having a multiplicity of slots 51 cut therein with tongues or prongs 52 extending therebetween and integrally connected with the upper portion 30a of the shutter 30. The vertically movable shutter 31 shown in Figs. 4-7 is provided with a plurality of depending tongues or prongs indicated at 53 separated by slots 54. It will be observed that the tongues or prongs 53 of the shutter 31 are laterally offset with respect to the center lines of the tongues or prongs 52 of the shutter 30. When the microammeters 23 and 24 are not energized, the shutters 30 and 31 are normally maintained out of the line of vision through slit 50 in shutter 29. A beam of light therefore passes through slit 50 from light source 16 and is swept across the field of lens 19 and activates light sensitive cell 15. However, should microammeter 23 be energized, the vertical shutter 31 is moved vertically to a position where the prongs or, tongues 53 extend into the path of the aperture or slit 50, thereby enabling the light beam to be broken up in ac- The angularly movable cordance with the movement of shutter 29 at a rate dependent upon the spacing 54 between the prongs 53 of shutter 31. Each microammeter 23, 24 and 25 is independently energized. Shutter 30 is moved into the field of movement of shutter 29, the prongs or tongues 52 extending substantially in overlapped relation with respect to the tongues or prongs 53 shown in Fig. 2, still leaving however, light apertures through the composite superimposed shutters 30 and 31, the spacing between which determines the rate at which the light beam through slit 50 is interrupted. An aperture plate 32 extends between the casing portion 48 and the casing portion 4'7. The aperture plate 32 contains light apertures 32a, 32b, 32c, 32d, 32c, and 32 etc., so that the light beam is still further broken up according to the composite movement of shutters 29, 30 and 31. That is, where the vertical shutters 30 and 31 are out of the path of light rays through the shutter 29, the light passes through aperture 50 and is broken up by the effect of the aperture plate 32 on the light ray.

That is, the light sensitive cell 15 will be activated for periods depending upon the rate of movement of slit 50 across each of the apertures 320-32) while the light sensitive cell 15 is not activated for the time periods over which the light ray is blocked or masked in its passage through the slit 50 by the portions of the aperture plate 32 extending between the apertures 820-32! therein.

When vertical shutter 31 moves over shutter 29. the time intervals over which the light sensithe cell 15 is energized is decreased for the reason that the prongs or tongues 53 tend to further mask the e 'of light rays through the lens system upon the light sensitive cell 15. When shutter 30 moves into superimposed relation with respect to shutter 31 and aperture plate 32, the time intervals over which the light sensitive cell 15 is activated are still further reduced. The housing portion 49 oi'thecasing is divided into three parts by partition plates 35 and 36. In the center compartment there is arranged a glow lamp designated at 1'1 with a reflector 34 positioned adjacent thereto for directing light rays through a central aperture 35a in partition plate 35, the light being directed upon the light sensitive cell 18 in the end compartment oi housing 49. Binding posts are brought out for connection oi. the interrupter in the control circuits. Binding posts 1 and 2 are provided for light sensitive cell 15. Binding posts 3 and 4 are provided for establishing connections with the winding of the microammeter 25. Binding posts 5 and 6 are provided for establishing connections with the windings of microammeter 24. Binding posts '7 and 8 provide connection to the winding of the microammeter 23. Binding posts 9 and 10 provide means for completing connections with the constant light source 16 located adjacent the reflector 33. Binding posts 11 and 12 connect with the glow discharge tube 1'? while binding posts 13 and 14 connect-with the light sensitive 'cell 18. Corresponding numbers for the several parts have been used in the several drawings to which cross reference may be made for a complete understanding of the details 0! my invention.

In Figs. 1 and la the connections to each of the elements within the interrupter have been shown as leading to binding posts numbered in a manner corresponding to the numbers shown in Fig. 2. The audio interrupters are again equal in construction, one interrupter being added for each sound to be used in the studio.

Referring in detail to the circuits of Figs. 1 and 1a it will be observed that the directors microphone 43 connects through line system 44 with the input circuit of amplifier No. 1 and with the binding posts 3 and 4 through microammeter winding 25 and through the master switch 55.

Beioreany of the sound channels to the studio may be rendered effective, the master switch 55 must be'closed. Switch 55 is closed when it is desired to obtain the effect of the several audio in'terrupters. The glow discharge lamp 17 connects in circuit with the amplifier in the directors microphone circuit through binding posts 11 and 12 and changes in its luminosity according to changes in amplitude 'in the director s microphone circuit. This results in energizing the microammeter or galvanometer winding 25 and effects a sweeping movement of the horizontal shutter 29 so that a beam of light from light source 16 sweeps over the light sensitive cell 15. It will be observed that the light sensitive cell 15 is effectively in series with light sensitive cell 18 through circuits extending between binding posts 1-2 and 1314, which binding posts connect with the input circuit of the output amplifier No. 1 which in turn connects to the loud speaker 1. The light sensitive cell 15 is merely subjected to light of constant intensity and serves only as a circuit closer through the input circuit of the output amplifier No. 1. The modulation control for the input circuit of the output ampliiler'No. 1 is obtained directly from the light sensitive -cell 18 which is controlled by the variation in the amplitude of glow discharge tube 17 which is in turn controlled by the directors microphone circuit. The microammeters 23 and 24 are controlled independently ot microammeter 25, but it will be observed that the several audio interrupters Nos. 1, 2 and 3 are coordinated in such manner that when the horizontal shutter 29 is moved in audio interrupter No. 1, the vertical shutter 23 in audio interrupter No. 2 is energized through binding posts 7 and 8, the circuit being completed through leads 56 and 57, and a vertical shutter actuated by microammeter 24 in audio interrupter No. 3 is operated through leads 58 and 59. It will also be observed that when microammeter 25 in audio interrupter No. 2 is actuated, that microammeter 24 of audio'interrupter No. 1 is operated through leads 60 and 61. Similarly, microammeter 23 of'audio interrupter No. 3 is activated simultaneously with the activation of microammeter 25 of audio interrupter No. 2 through leads 62 and 63. This produces the effect of moving a horizontal shutter in one audio interrupter while vertical shutters are moved in other audio interrupters.

When music is supplied from music room 45 to the studio 40, the selection 01' phonograph music or band concert music, or other source of entertainment, is selected by means oi double pole double throw switch 64 which when thrown to the left connects in the phonograph control circuit indicated at 65 and when thrown to the right connects in the microphone control circuit indicated at 66. The input amplifier No. 2 is connected in the control circuit and connects to the winding 25 of the microammeter in audio interrupter No. 2 which results in the horizontal scanning movement of shutter 29 in audio interrupter No. 2. Simultaneously, the vertical shutter driven by microammeter 24 in audio interrupter No. 1 is actuated and simultaneously the vertical shutter driven by microammeter winding 23 in audio interrupter No. 3 is activated. The output from audio interrupter No. 2 leads from light sensitive cells 15 and 18 disposed in series by which the input of the output amplifier No. 2 is energized as a result of which loud speaker 2 in the studio is operated. The music from music room 45 modulates the glow discharge tube 17 through leads 62 and 63. The luminosity of tube 17 varies and correspondingly controls light sensitive cell 18 thus controlling the output ampliher No. 2 and actuating loud speaker 2. However, the period of activation of loud speaker 2 depends wholly uponthe length of time that light sensitive cell 15 may beenergized according to the movement of the several shutters.

The energy for the constant sourses of light 16 is obtained from source of potential indicated at 65a and controlled by switch 66a.

The monitor circuit over which the operator who maintains constant watch upon the condition of the recording apparatus may talk, extends from microphone 46 through the input amplifier No. 3 to the terminals 3-4 of audio interrupter No. 3 by which horizontal movement of the shutter 29 is eiiected. It will be observed, however, that the microammeter winding 24 which operates a vertical shutter in audio interrupter No. 2 and microammeter winding 23 which operates a vertical shutter in audio interrupter No. 1 are simultaneously operated with the movement or the horizontal shutter 29. Simultaneously glow dis charge tube 17 has its luminosity varied under control of the monitor microphone circuit through leads 6'7 and 68, the circuit being completed when switch 55 is closed. Change in the luminosity of tube 17 results in changes in conductivity of light sensitive cell 18' in audio interrupter No. 3 and with the energization of light sensitive cell 15 as a. condition precedent the input circuit of the output amplifier No. 3 is energized and the loud speaker 3 in the studio operated to convey the voice of the monitor to the artist or director.

Microphone 42 in the studio connects to double pole double throw switch 69 through an input amplifier designated at 70. When switch 69 is thrown to contacts '71, the winding 25 of the microammeter which moves the horizontal shutter is activated in an apparatus which I-have termed an audio selector shown at 73. The apparatus indicated at 73 as shown more clearly in Fig. 15 differs from the apparatus which I have termed the "audio interrupter shown at No. 1', No. 2 and No. 3 and which has been shown in detail in Figs. 2 and 3 in that the aperture plate 32 is omitted and a vertical shutter 103 operated by an actuating mechanism '72 (see Fig. 1) has been added. The additional vertical shutter 103 is moved by the microammeter '72 which shutter is similar to the structure of shutters 30 and 31 but the prongs or tongues thereof are displaced to further overlap the tongues or prongs 52 and 53 of vertical shutters 30 and 31. This arrangement of shutters tends to further decrease the time intervals over which the light sensitive cells 15 and 18 are activated. Simultaneously with the movement of the vertical shutter controlled by microammeter 25, the glow discharge tube 17 varies in intensity according to the modulation effected through microphone 42. The control circuit may be opened to switch 74a. The light sensitive cell 18 is varied in its resistance according to the change in luminosity of the glow discharge tube 17 and with the circuit through light sensitive cell 15 completed the output circuit extends through leads 74 and 75 to the stage microphone output amplifier 76 and to the switch '77 which may be thrown in closed position to complete recording circuit No. 2 designated at '78. The only sounds in circuit 78 to recording circuit No. 2 are the wanted sounds for the reason that the shutters operated by microammeters 23, I24 and 72 in the audio selector 73 block any light "which may be modulated according to the director's microphone or according to sound emanating from the music room 45 and the monitor microphone 46. This will be more clearly understood when it is observed that in the audio selector "73 the microammeter winding 24 connects through binding posts 5 and6 with the circuit controlled effectively with the monitor microphone circuit 46 through leads 80 and 81. It will also be noted that the vertical shutter controlled by microammeter winding 23 connects through binding posts the height of the apertures.

directors microphone circuit 43. The additional vertical shutter operated by winding 72 connects through binding posts 84 and 85 and through leads 86 and 87 efiectively with the music room modulation circuit through input amplifier No. 2.

It will therefore be seen that the audio selector provides means whereby operation of any of the microphone circuits 43, 46 or the music room circuit 45 masks or blocks the passage of light from the light source 16 in the audio selector '73 preventing the light from reaching the light sensitive cell 15 except at one time interval. The wanted sounds activate the circuit at this one time interval which recur periodically enabling the wanted sounds to be passed to recording circuit No. 2 independent of any of the unwanted sounds. However, if it is desired to record the unwanted sounds connections may be taken from the several photoelectric cell control circuits through leads designated at 90 and through switch 91 for connection tocontacts 92 leading to a recorder circuit. It may also be desirable to record both the wanted and unwanted sounds in which event double pole double throw switch 89 may be moved to the right hand side shown at 93 whereupon leads 94 extend to recording circuit N o. 3 for recording all of the sounds picked up in the studio.

It will be understood that sound records may be made upon films, discs or.magnetic wire records in any of the recording circuits Nos. 1, 2 or 3. Where the record is clear of unwanted sounds such as is obtained in recording circuit No. 2, any of the usual projecting processes may be employed for the reproduction of the sounds. However, where the sound record is confused such as is obtained in the recording circuit No. 3 with both the wanted and unwanted sounds, the projection process employs a system of elements embodying the principles of my invention as hereinbefore described.

I have developed a specific formula or accurately determining the size of the slots in the ver-. tical shutters. The distance between the prongs 53 and 52 in the audio interrupter and between the prongs in the audio selector of shutters 31, 30 and 103 may be derived by computing this distance as equal to the number of unwanted sound channels employed in the system plus the constant 1 multiplied by the width of the aperture 50 in the horizontal shutter 29. ,That is, if two unwanted channels are to be used, viz., a dire'ctors voice channel and a monitor's voice channel, the centers between the prongs in the shutters will be: 2 1+1=3Xthe width of the aperture in the horizontal shutter.

The length of the prongs will be determined by the number of apertures 32a32,f in the aperture plate 32 01' Figs. 13 and 14 multiplied by The horizontal shutter 29 has a single aperture 50, the height of which is equal to the height of the several apertures in the aperture plate 32 and the width of which is equal to the width of the prongs 52 or 53 in the vertical shutters. The aperture plate 32 contains apertures 32a32f having height which is equal to the height of the aperture 50 in the horizontal shutter 29. The width 01' the apertures 32a32f is equal to the constant 1 multiplied by the number of unwanted channels multiplied by the width of the aperture 50 in the horizontal shutter. The distance from center to center of the apertures 32a32f is equal to the 7 and 8 andieads 82 and 83 effectively with the constant 1 multiplied by the number of unwanted channels used plus the constant 1 multiplied by the width of the aperture 50 in the horizontal shutter 29. The apertures 3211-32) are equal divisions of the width of the prongs in the -vertically moving shutters and the solid interconnecting portion between the apertures in the aperture plate 32 are of a width equal to the Width of one prong. The multiplicity of prongs are so arranged that the light may be completely shut off by the-echelon movement of the prongs. The prongs are so aligned with the apertures 32a32f that the amount of light passing through the apertures 32a-32f is decreased in accordance with the successive operation of the shutters. That is, .the movement of one vertical shutter into position decreases the amount of light which passes through the optical system and the movement of the next vertical shutter further reduces the light which passes the apertures 32a,-32f. A more detailed understanding of the arrangement of the vertical and horizontal shutters will be had from a consideration of Figs. 412 from which it will be noted that the construction of the vertical shutters is such that the prongs are offset one with respect to another. That is, in considering Figs. 4 and 8, it will be seen that the prongs 52 and 53 overlap one with respect to another. While the aperture plate 32 shown more clearly in Figs. 13 and 14 remains stationary, the horizontal shutter 29 moves in a horizontal'direction so that aperture 50 alternately registers with the apertures 32a-'-32f and successively light will be further out ofi by the successive movement of the vertical shutters.

Inasmuch as each light beam corresponding to the width of one of the prongs constitutes the activating means for one of the sound channels, it will be understood that the several sound channels may be successively rendered effective by the optical control system of my invention.

. The principles of my invention are also applicable to multiplex telephone and telegraph systems. That is, the apparatus of my invention provides an electrical cut off for rendering the same electrical circuit effective to carry successive portions of different signaling channels 'which 7 renders the same line system capable of carrying a multiplicity of telegraph or telephone messages simultaneously.

While I have described a preferred embodiment of my.,invention, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. Control apparatus comprising a casing hav-' ing a central section and a pair of oppositely extending end chambers connected with said central section, a light source in one of said end chambers, a condenser lens system disposed within said last mentioned end chamber in alignment with said light source, a multiplicity of independently operative shutter members operating in different planes within said central section in alignment with said light source, a lens system disposed in the other of said end chambers and a light sensitive cell disposed at the focal point of said last mentioned lens system and subject to the action of rays of light from the light source in the first mentioned end chamber under control of said shutter members.

2. A control apparatus comprising a casing having a central enlarged section, a pair of end chambers projecting radially from said central section, a light source in one of said end chambers, a lens system in both of said end chambers, a light sensitive cell in the other of said end chambers in the path of said lens systems and a multiplicity of shutters independently operative in difierent planes disposed within said central section in the path of the light rays from said light source through said lens systems and for controlling the effect of said light source upon said light sensitive cell.

3. A control apparatus comprising a casing having a centralsection and an end section on each side thereof, a partition dividing one of said end sections into two portions, a light source on each side of said partition, the light source onone side of said partition directing light rays upon a light sensitive cell within the end chamber containing said partition and the light source on the other side of said partition directing light rays upon a light sensitive cell in the other of said end chambers, and a plurality of shutters independently operative in difierent planes within said-central section for controlling the effect of the light rays upon said last mentioned light sensitive cell. i

. 4. A control. apparatus comprising a casing having an enlarged central section and a pair of upwardly extending chambers, a light sensitive cell disposed in the extremities of, each of' said end chambers, a partition member in one of said end chambers, a light source on each side of said partition member for independently controlling said light sensitive cells, and means disposed within said central section in the path of the light rays from the light source in one of said end sections to the light sensitive cell in the other of said end sections for controlling the operation of said last mentioned light sensitive cell.

5. A control apparatus comprising a casing having a central section and a pair of oppositely extending end chambers, one of said end chambers having a partition extending therethrough, a light source on each side of said partition, a light sensitive cell in the extremity of each of said 30 end chambers, the light source on one side of said partition being directed upon the light sensitive cell inthe end chambercontaining said partition and the light source on the other, side of said partition being directed upon a photo- 35 electric cell in the other of said end chambers, and a plurality of overlapping shutters operative in different planes in said central section in the path of said light rays for controlling the time periods of operation of said last mentioned 140 light sensitive cell.

JOSEPH RENAULT mt LA CROIX. 

